THE LATERAL LINE ORGANS. 39 



which is supplied by the r. lateralis vagi. There are 

 three dorsal branches of the lateral line nerve, of which it 

 is clear from the description that only one contains proper 

 lateralis fibres. The first of these is an opercular nerve 

 which goes to the skin of the operculum, the "superficial 

 opercular," and evidently corresponds to my branches 

 cut. X. 2 and ait. X. j (see Section 5, VIII). It also sends a 

 branch, the " opercularis profundus," which anastomoses 

 with the r. opercularis profundus VII and supplies the 

 lining of the branchiostegal rays and which evidently cor- 

 responds to my branch n. op. X. The second dorsal 

 branch is motor and apparently corresponds in part to my 

 branch for the trapezius muscle {XI). The third dorsal 

 branch is the proper supra-temporal nerve. It supplies 

 the lines (see fig. 6) p-o, p-b, o-b and b-l. These lines evi- 

 dently represent the supra-temporal commissure and cer- 

 tain of the pit-lines found in Amia. 



The lines b-d., d-e^ d-k, e-li., e-f, f-g and f-m are all in- 

 nervated by the r. mandibularis externus facialis, and 

 correspond to the operculo-mandibular lines of Menidia. 

 In Lophius there are some anastomoses of these nerves 

 with the r. mandibularis trigemini, but there is no evi- 

 dence that any of the lateralis fibres come from the latter 

 source. The r. mandibularis externus VII is not, as 

 in Menidia, a single nerve, but is broken up into several 

 independent nerves. Thus, the lines b-d^ d-e, d-k and 

 e-h are supplied by a single branch which Guitel calls the 

 r. opercularis superficialis VII, and which corresponds 

 to that nerve in Menidia plus a portion of the main r. 

 mandibularis externus VII. The line b-d-e-f-m corre- 

 sponds to the operculo-mandibular line. The other lines 

 of this series I think are to be compared with pit-lines of 

 some other forms. Thus, the line e-h corresponds in 



